Zhou Y, Iacocca E, Awad A A, Dumas R K, Zhang F C, Braun H B, Åkerman J
York-Nanjing Joint Center for Spintronics and Nano Engineering (YNJC), School of Electronics Science and Engineering, Nanjing University, Nanjing 210093, China.
Department of Physics, The University of Hong Kong, Hong Kong, China.
Nat Commun. 2015 Sep 9;6:8193. doi: 10.1038/ncomms9193.
Magnetic skyrmions are topologically non-trivial spin textures that manifest themselves as quasiparticles in ferromagnetic thin films or noncentrosymmetric bulk materials. So far attention has focused on skyrmions stabilized either by the Dzyaloshinskii-Moriya interaction (DMI) or by dipolar interaction, where in the latter case the excitations are known as bubble skyrmions. Here we demonstrate the existence of a dynamically stabilized skyrmion, which exists even when dipolar interactions and DMI are absent. We establish how such dynamic skyrmions can be nucleated, sustained and manipulated in an effectively lossless medium under a nanocontact. As quasiparticles, they can be transported between two nanocontacts in a nanowire, even in complete absence of DMI. Conversely, in the presence of DMI, we observe that the dynamical skyrmion experiences strong breathing. All of this points towards a wide range of skyrmion manipulation, which can be studied in a much wider class of materials than considered so far.
磁斯格明子是拓扑非平凡的自旋纹理,在铁磁薄膜或非中心对称块状材料中表现为准粒子。到目前为止,研究重点一直集中在由Dzyaloshinskii-Moriya相互作用(DMI)或偶极相互作用稳定的斯格明子上,在后一种情况下,激发被称为泡状斯格明子。在此,我们证明了一种动态稳定的斯格明子的存在,即使在没有偶极相互作用和DMI的情况下它也能存在。我们确定了在纳米接触下的有效无损介质中,这种动态斯格明子如何能够成核、维持和操控。作为准粒子,它们甚至在完全没有DMI的情况下也能在纳米线中的两个纳米接触之间传输。相反,在存在DMI的情况下,我们观察到动态斯格明子会经历强烈的呼吸运动。所有这些都表明存在广泛的斯格明子操控方式,这可以在比目前所考虑的更为广泛的一类材料中进行研究。